Dear Scott, * Scott Cotton <w...@iri-labs.com> [2018-10-28 10:49]: > I don't know if you're "doing it the right way", however, pitch shift by > bin shifting has > the following problems: > > -edge effects (using windowing can help) > - pitch shift up puts some frequencies above nyquist limit, they need to be > elided > - the quantised pitch shift is only an approximation of a continuous pitch > shift because > the sinc shaped realisation of a pure sine wave in the quantised frequency > domain can occur > at different distances from the bin centers for different sine waves, > shifting bins doesn't do this > and thus isn't 100% faithful. > > From the sound clip, I'd guess that you might have some other problems > related to normalising the > synthesis volume/power > > The best quality commonly used pitch shift comes from a phase vocoder TSM: > stretch the time > and then resample (or vice versa) so that the duration of input equals that > of output. Phase vocoders > however vary a lot in the quality of sound they produce, some are even as > bad or worse than the example > you provided.
Thank you for this nice explanation, I wonder if you could even add a few more lines to it regarding the quality of phase vocoders. Your text ended when it was getting even more exciting. :) Thanks! P _______________________________________________ dupswapdrop: music-dsp mailing list music-dsp@music.columbia.edu https://lists.columbia.edu/mailman/listinfo/music-dsp
